Radiotherapy apparatus

Abstract

A radiotherapy apparatus adapted for use with a Magnetic Resonance Imaging (MRI) system, the radiotherapy apparatus comprising a linear accelerator, the linear accelerator including an electron source. In the linear accelerator electrons which are introduced by the source are accelerated to impact on a target and produce a beam of radiotherapeutic radiation. The linear accelerator has an accelerator waveguide within which the electrons are accelerated and an external waveguide enclosure; this enclosure extends substantially continuously over the accelerator waveguide. The waveguide enclosure is formed of a high magnetic permeability material and has a first aperture for the beam of radiotherapeutic radiation where the beam exits the waveguide enclosure and enters the MRI system and a second aperture for an RF guide for the introduction of electrons into the accelerator waveguide and for electrical lines for the particle source and coolant lines for the waveguide to pass through the enclosure and no other openings. The waveguide enclosure is preferably fabricated in a plurality of discrete parts.

Description

technical field [0001] The present invention relates to radiotherapy devices, in particular but not limited to magnetic resonance (MR) guided linear accelerator devices. Background technique [0002] Radiation therapy devices are well known in which a radiation source emits a beam of radiation directed at a patient in order to destroy or otherwise injure cancer cells within the patient. Many designs of radiotherapy equipment employ radioactive sources, such as linear accelerators (linacs) for high-energy (MV) X-radiation, or isotope sources, such as cobalt-60, mounted on the arms of elongated gantry (gantry) arms that The gantry arms are rotatable about a patient support on which a patient can be placed for treatment. The source is rotatable so it can be rotated around the patient to irradiate the desired area from a number of different directions, thereby reducing the dose applied to healthy tissue outside the desired area. The beam is typically collimated so as to limit ...

AI Technical Summary

Problems solved by technology

[0010] The present invention is based on the realization that suitable magnetic shielding in the MRL can simultaneously address the problems of preventing linac beam deflection caused by the high static magnetic field of the MR system and the high voltages used in the linac from adversely affecting MR image quality. Problem, therefore, the present invention provides a radiotherapy apparatus adapted for use with a Magnetic Resonance Imaging (MRI) system, the apparatus comprising a linear accelerator adapted to be mounted to an outer surface of the MRI system and having an accelerator waveguide derived from Electrons / particles of an electron (or other particle) source are accelerated within the accelerator waveguide to impinge on the target and generate a radiotherapy radiation beam, the apparatus having an outer waveguide envelope extending substantially continuously around the exterior of the accelerator waveguide, the The waveguide enclosure is formed from a high magnetic permeability material and has: a first aperture for the radiotherapy radiation beam, wherein the beam exits the waveguide enclosure and enters the MRI system; and a second aperture for RF guides to introduce electrons into the accelerator waveguide and for cables and coolant lines to the waveguide accelerator to pass through the enclosure, wherein an interface flange is provided for mounting the accelerator waveguide and the waveguide enclosure on one side Between the exterior of the MRI system on the other side, the flange includes a waveguide envelope end cap formed of a high magnetic permeability material in which the first aperture is located, substantially in the waveguide envelope There are no additional holes or breaches

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